Irrigation sprinklers are known for watering circular patterns using essentially a single rotary water stream that is rotated in a circle around a vertical rotational axis. This water stream is thrown by a sprinkler nozzle mounted in the peripheral sidewall of the nozzle body. The sprinkler nozzle is upwardly angled relative to the horizontal so that the water stream being thrown by the nozzle is projected at some given trajectory relative to the horizontal to water a circular pattern having a particular radius. A full circular pattern is watered by such a sprinkler when the sprinkler is rotated uni-directionally. However, the drive means for such a sprinkler can reverse the rotation of the nozzle body, if so desired, to water pie-shaped arc segments that are less than a full circle.
Rotary sprinklers of the type just described have long been manufactured and sold by The Toro Company, the assignee of this invention. For example, the Toro Super 600, Super 606 and Super 700 sprinklers are of this type. In addition, U.S. Pat. No. 3,724,757, which is owned by The Toro Company, illustrates and describes a sprinkler of this type.
In sprinklers using a side mounted nozzle to throw a single primary water stream for watering the desired area, it is relatively difficult to change the flow volume of the stream being thrown by the nozzle. This is most often done by physically removing one nozzle and replacing it with a nozzle having either a larger or smaller water flow area therein to change the flow volume or gallonage capacity of the nozzle. It is difficult to remove the nozzle because the nozzle is recessed inside the nozzle body and cannot be gripped sufficiently to pull it out against the force of the press fit. Thus, the user often needs a tool, such as a screwdriver, which is inserted into the spray apertures of the nozzle to pry the nozzle out of the nozzle seat.
The disadvantages in this approach to adjusting the flow volume of the sprinkler are apparent. The user needs to have available a supply of replacement nozzles of different gallonage capacities to have one corresponding to the capacity that may be needed at the time, and has to have such nozzles with him or her at the time the adjustment is desirably made. Moreover, if the sprinkler is operating at the time one wishes to change the nozzle size, the user first has to shut the sprinkler off which may require going to a remote location to turn off the water supply to the sprinkler. Once the nozzle change is made, another trip back to the water supply is required to turn the water supply back on. In addition, the old nozzle first has to be removed which often damages or destroys the old nozzle preventing its reuse. The need to have a set of differently sized nozzles, and the need to engage in nozzle removal and replacement just to change the gallonage being thrown by the nozzle, increases the cost of such sprinklers and the difficulty of changing the flow volume of the sprinkler.
Undoubtedly, some sprinklers are installed or left in place with nozzles throwing too much or too little water. The user is simply deterred from properly adjusting the flow volume because he or she does not have the right nozzle on hand, or does not wish to remove the nozzle that is already installed, or does not wish to interrupt the water flow to an operating sprinkler.
Most sprinklers of this type also have what is known as a radius adjustment screw for changing the trajectory of the water stream being thrown by the nozzle to adjust the throw radius of the sprinkler. This screw, which is accessible from the top wall of the nozzle body, has a lower end which is screwed down in front of the nozzle to deflect downwardly the stream exiting from the nozzle to adjust the radius of throw. The amount of the deflection depends on the degree to which the lower end of the screw protrudes into the water stream. This screw engages against the top of the front face of the nozzle to help keep the nozzle in place in the seat.
This method of radius adjustment has various problems. Using a screw to protrude into the water stream causes the water stream to laterally spread or split apart in other unpredictable and undesirable ways. This can cause unpredictable and undesirable changes in the precipitation rate provided by the sprinkler. In addition, as the screw protrudes more and more into the water stream, situations will arise where the radius of throw may actually begin to increase again. Thus, it is difficult to get the sprinkler to water a very short radius, i.e. relatively close to the sprinkler itself, using a conventional radius adjustment screw.